Flickr Commons is a website that brings together a wide range of public photography collections.

For photographs, there are commercial image banks like Getty Images. Paul Frosh's (2003) book on image banks is an excellent critical account of how they work. See below for more examples.

There are also specialist image banks: ARKive, for example, specialises in wildlife photographs, and RIBApix specialises in photographs of architecture of all periods together with related subjects such as interior design, landscape, topography, planning, construction and the decorative arts.

Advertolog is an online collection of recent adverts, divided into print/outdoor and tv/film/digital. You can search by brand, product and advertising agency. Ads of the World does a similar job, though is a bit less user-friendly, I found. Campaign is the advertising profession's magazine in the UK. It carries both discussion of adverts, and a collection of all sorts of advertising too. For older advertising, Advertising Archives has a lot of print images, and some screen shots of television commercials. The History of Advertising Trust has an online gallery of UK ads, with adverts collected into themes as well as a search function; their online gallery is a taster of their physical archive which is held in Norwich, UK.